Shaking machines, or vibrating machines, have been widely used for many purposes, especially in foundries where they find use in consolidating molding sand in the foundry flasks and also in loosening and removing core sand from hollow castings.
Such machines have generally consisted of a pneumatic hammer acting on the article which is to be shaken or its support. Such shaking machines, while sometimes extremely effective, produce deafening noises and troublesome vibrations and are not always effective for their intended purposes. Moreover, the hammering action causes more or less rapid destruction resulting in considerable maintenance and renewal to keep the machines in operation.
Other types of machines for producing vibration solely by reversible fluid impulses are known but are complex in structure, involving energy losses and wear in moving parts and have accordingly been proposed primarily for investigating effects of vibration rather than for commercial use in manufacturing operations.
An object of this invention, accordingly, is to produce a simple and reliable machine for producing intense and effective vibration without troublesome noise and with only a small consumption of energy. A specific object is to provide a machine for rapid, effective and economical loosening and removal of core sand from hollow castings.